diff --git a/triagebot.toml b/triagebot.toml
index b684f3ca55c64..a9ddd1b99c72a 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -1,3 +1,6 @@
+# This file's format is documented at
+# https://forge.rust-lang.org/triagebot/pr-assignment.html#configuration
+
 [relabel]
 allow-unauthenticated = [
     "A-*",
@@ -646,6 +649,7 @@ compiler-team = [
 compiler-team-contributors = [
     "@TaKO8Ki",
     "@b-naber",
+    "@nnethercote",
 ]
 compiler = [
     "compiler-team",
@@ -702,6 +706,9 @@ lexer = [
     "@nnethercote",
     "@petrochenkov",
 ]
+arena = [
+    "@nnethercote",
+]
 mir = [
     "@davidtwco",
     "@oli-obk",
@@ -735,7 +742,6 @@ style-team = [
     "@joshtriplett",
     "@yaahc",
 ]
-
 project-const-traits = [
     "@compiler-errors",
     "@fee1-dead",
@@ -754,6 +760,7 @@ project-stable-mir = [
 "/Cargo.lock" =                              ["@Mark-Simulacrum"]
 "/Cargo.toml" =                              ["@Mark-Simulacrum"]
 "/compiler" =                                ["compiler"]
+"/compiler/rustc_arena" =                    ["compiler", "arena"]
 "/compiler/rustc_ast" =                      ["compiler", "parser"]
 "/compiler/rustc_ast_lowering" =             ["compiler", "ast_lowering"]
 "/compiler/rustc_hir_analysis" =             ["compiler", "types"]
@@ -780,7 +787,7 @@ project-stable-mir = [
 "/library/panic_unwind" =                    ["libs"]
 "/library/proc_macro" =                      ["@petrochenkov"]
 "/library/std" =                             ["libs"]
-"/library/std/src/sys/pal/windows" =             ["@ChrisDenton", "@thomcc"]
+"/library/std/src/sys/pal/windows" =         ["@ChrisDenton", "@thomcc"]
 "/library/stdarch" =                         ["libs"]
 "/library/test" =                            ["libs"]
 "/src/bootstrap" =                           ["bootstrap"]